Toyota Motor Corporation has said it has suspended its operations at all 14 of its domestic assembly plants, Reuters reports.

The cause is a system malfunction, preventing the automaker from ordering components.

A spokesperson has said the cause was unlikely to be a cyberattack and the issue is being investigated.

The system failure comes at a time when Japanese businesses and government offices have been receiving ‘harassing’ phone calls, which Japan says were likely from China, due to the recent decision to release treated radioactive water from the Fukushima nuclear plant into the Pacific Ocean.

However, a Toyota spokesperson has said the cause was unlikely to be a cyberattack, and the issue is being investigated.

Last year the automaker suspended operations for a day when a supplier was targeted by a cyberattack.

The 14 plants make up approximately a third of Toyota’s global production, Reuters estimates.